This competing continuation aims to understand how risk-taking develops across adolescence as a function of biological maturation (puberty and age) and socialization (parenting and culture). We have started the largest known prospective study of these processes by recruiting a sample of 1,417 8-year-olds and their mothers and fathers from 13 cultures (Jinan and Shanghai, China; Colombia; Naples and Rome, Italy; Jordan; Kenya; Philippines; Sweden; Thailand; and African, European, and Hispanic Americans in the United States). We have assessed families annually through interviews with mothers, fathers, and children about the parent-child relationship; the child's adjustment; attitudes and beliefs; and cultural values and are currently assessing self- regulation among the children, who are now age 10. During the next period, we will conduct interviews annually with mothers, fathers, and adolescents to assess their relationships and adolescents' risk-taking. We will also assess adolescents' reward-seeking, self-regulation, social information processing, and risk-taking via a computerized battery administered at ages 12, 14, and 16. Our first aim is to test hypotheses regarding the roles of biological maturation and socialization in the development of risk-taking. To the extent that changes in risk-taking during adolescence are biologically driven, one would expect to find comparable developmental trajectories of risk-taking across all cultures. In contrast, to the extent that changes are shaped by parenting and culture, we would expect to find variations in the development of risk-taking that are linked to specific features of parent-child relationships and cultural contexts. Our second aim is to understand psychological mechanisms through which biological maturation, parenting, and culture alter the development of risk-taking. We will test hypotheses that adolescents' reward-seeking, self-regulation, and acquired social information processing patterns mediate the impact of puberty, parenting, and culture on adolescents' risk-taking. Our third aim is to test the hypothesis that formativeness of parenting behaviors and culturally shaped opportunity for risk-taking moderate the relation between parenting and adolescents' risk-taking. We hypothesize that individual differences in adolescent behavior will be predicted by differences in parenting, but also that addictiveness of parenting depends on its cultural formativeness. In addition, we hypothesize that the relation between parenting and any particular form of adolescent risk-taking will be weaker in cultural contexts in which there are few opportunities to engage in that form of risk-taking. This study wil utilize the most culturally diverse and largest sample of young people and their parents ever assembled as an unprecedented opportunity to understand biological, parenting, and cultural processes in the development of adolescent risk-taking. It will inform theories of the nature of adolescent development and will shape interventions to prevent health-compromising and illegal risky behaviors.